Anti-tamper mesh

ABSTRACT

An electronic device includes at least one terminal formed on the electronic device. The electronic device also includes at least one of a semiconductor device, an integrated circuit chip, and a computer. A seamless conductive mesh is formed on at least one surface of the electronic device. The conductive mesh is in electrical contact with the terminal. The terminal facilitates electrical conduction between the conductive mesh and an electrical detection circuit. The electronic device also may include a pattern having traces formed on at least two surfaces where each of the traces includes a continuous loop of conductive material is formed on at least two surfaces. The electronic device also may include a first plurality of conductive loops formed on the electronic device that are continuous and surround the electronic device in a first direction and a second plurality of conductive loops formed on the electronic device that are continuous and surround the electronic device in a second direction.

CROSS-REFERENCE TO RELATED APPLICATIONS/PRIORITY CLAIM

This non-provisional application for patent is a continuation patentapplication of U.S. application Ser. No. 11/944,771 now U.S. Pat. No.7,947,911, filed Nov. 26, 2007, which is a divisional patent applicationof U.S. application Ser. No. 11/252,402 now U.S. Pat. No. 7,640,658,filed Oct. 18, 2005, the disclosure of each is herein incorporated byreference in its entirety.

BACKGROUND

Anti-tamper (“AT”) protection is employed so that it is very difficultto reverse engineer or alter the function of electronic hardware (e.g.,computer processors, integrated circuits, multi-chip modules, etc). Forsome commercial applications, designers often spend vast sums of moneyto develop a “next generation” circuit. These companies often wish todeter, or at least hamper a competitor's reverse engineering efforts.The motivation in this case is to protect valuable intellectualproperty. Military and Government users also have a strong interest inAT protection. When new military hardware is fielded, often theconsequences of capture are not fully understood by the designer of thehardware. Similarly, the combat loss of any one of a thousand pieces ofsensitive, high-tech military hardware could do irreparable damage tonational security.

Most AT is categorized as either passive or active. In each case, theintent is to delay, prevent or stop tampering and potential reverseengineering of an electronic circuit. Passive AT is currently the mostwidespread method of deterring an opponent from reverse engineering orspoofing an electronic circuit. Current passive AT arrangements includeencapsulation or various types of conformal coatings such as epoxies.Methods to defeat common encapsulants are well documented.

AT standards have been defined according to the Federal InformationProtection Standard (FIPS) 140-2. The standard describes therequirements for four levels of protection. For the standards formulti-chip, embedded modules, Level 1 calls for standard passivationtechniques (i.e., a sealing coat applied over the chip circuitry toprotect it against environmental or other physical damage). The standarddescribes that Level 2 can be achieved using anti-tamper coatings orpassive AT. Level 3 may use passive AT if tampering will likely destroythe module. Level 4 requires the use of active AT technologies.

Layered anti-tamper arrangements are also employed in which alternatinglayers of passive AT with active AT yields a synergy in probingdifficulty. With active AT methods, a protected circuit will take someaction when unauthorized activities are detected. Any number of eventscan trigger a programmed circuit response. Examples of active triggeringarrangements include: voltage, photon detection, acceleration, strain,thermal, chemical attack, and proximity or tamper-respondent enclosures.A tamper-respondent package can theoretically detect probing byproximity detection or by an external activity mutilating an activecircuit, exterior to what is being protected. The response of an activeAT circuit upon triggering is also widely variable. For example,zeroization may be employed in which critical memory cells or an entiredie can be erased. Similarly, a response can trigger overwriting of someor all of a memory die. Another detection response is to physicallyobliterate a critical circuit element or elements.

SUMMARY

In one embodiment, the present invention is directed to an electronicdevice. The electronic device also includes at least one terminal formedon the electronic device. The electronic device further includes atleast one of a semiconductor device, an integrated circuit chip, and acomputer. A seamless conductive mesh is formed on at least one surfaceof the electronic device. The conductive mesh is in electrical contactwith the terminal. The terminal facilitates electrical conductionbetween the conductive mesh and an electrical detection circuit.

In one embodiment, the present invention is directed to an electronicdevice. The electronic device includes a pattern formed on at least twosurfaces of the electronic device. The electronic device also includesat least one of a semiconductor device, an integrated circuit chip, andan electronic substrate. The pattern includes one or more than onetraces. Each of the one or more than one traces comprising a continuousloop of conductive material and being formed on at least two surfaces ofthe electronic device.

In one embodiment, the present invention is directed to an electronicdevice. The electronic device includes a first plurality of conductiveloops formed on the electronic device. Each of the first plurality ofconductive loops is continuous and surrounds the electronic device in afirst direction. The electronic device also includes at least one of asemiconductor device, an integrated circuit chip, and an electronicsubstrate. A second plurality of conductive loops is formed on theelectronic device. Each of the second plurality of conductive loops iscontinuous and surrounds the electronic device in a second direction.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1 through 11 illustrate an embodiment of a process for fabricatingan anti-tampering mesh on an electronic device.

DESCRIPTION

Various embodiments of the present invention include an electronicdevice that has an anti-tampering mesh that is fabricated on the device.In various embodiments, the conductive mesh is defined by single ormultiple conductive layers separated by alternating non-conductive (ordielectric) layers. The multiple conductive layers are electricallyconnected to the detection circuitry with the terminals by electricalvias extending through the dielectric layers. As used herein, the term“electronic device” can include, for example, any type of device orpackage such as a semiconductor device, an electronic package, anintegrated circuit chip, device or module, an electronic or electricalsubstrate, a circuit board, a packaged circuit, a computer, and thelike.

FIGS. 1 through 11 illustrate an embodiment of a process for fabricatingan anti-tampering mesh on an electronic device 10. In FIG. 1, terminals12 are created on a first dielectric layer 13, which covers all surfacesof the electronic device 10. The terminals 12 facilitate an electricalconnection from the circuits (not shown) that are contained on or in thedevice 10 to an anti-tampering mesh that is fabricated on the device 10as described hereinbelow. In FIG. 2, the terminals 12 are masked and thedevice 10 is coated with a first insulator layer 18. Conductive traces20 are then developed on surfaces 14, 16 to facilitate an electricalconnection from the circuits (not shown) that are contained on or in thedevice 10 to an anti-tampering mesh that is fabricated on the device 10as described herein.

In FIG. 3, the terminals 12 are masked and the device 10 is coated witha second insulator layer 22. The masks are then removed. In FIG. 4,conductive patterns 24 such as, for example, conductive polymerpatterns, are deposited using, for example, an inkjet printer 26. Theinkjet printer 26 may be, for example, a step-repeat inkjet type ofthick film printer or rotary head printer. The device 10 may be rotatedin, for example, the direction of the arrow 28 so that four sides of thedevice 10 may have conductive patterns 24 deposited thereon. Theconductive patterns 24 are cured by, for example, a UV light source 30.The UV light source 30 may be attached to the inkjet printer 26 suchthat the conductive patterns 24 are cured upon deposition by the inkjetprinter 26. The resulting device 10 is shown in FIG. 5.

In FIG. 6, the terminals 12 are masked and the device 10 is coated witha third insulator layer 32. The masks are then removed. In FIG. 7, thedevice 10 is rotated ninety degrees and conductive patterns 34, such asconductive polymer patterns, are deposited using, for example, theinkjet printer 30. The device 10 may be rotated in, for example, thedirection of the arrow 36 so that four sides of the device 10 haveconductive patterns 34 deposited thereon. The conductive patterns 34 maybe cured by, for example, the UV light source 30. The light source 30may be attached to the inkjet printer 26 such that the conductivepatterns 34 are cured upon deposition by the inkjet printer 26. Theresulting device 10 is shown in FIG. 8.

In FIG. 9, the terminals 12 are masked and the device 10 is coated witha fourth insulator layer 38. The masks are then removed. In FIG. 10,device 10 is rotated ninety degrees and conductive patterns 40, such asconductive polymer patterns, are deposited using, for example, theinkjet printer 30. The device 10 may be rotated such that four sides ofthe device 10 may have conductive patterns 40 deposited thereon. Theconductive patterns 40 may be cured by, for example, the UV light source30. The light source 30 may be attached to the inkjet printer 26 suchthat the conductive patterns 40 are cured upon deposition by the inkjetprinter 26. In FIG. 11, the terminals 12 are masked and the device 10 iscoated with a fifth insulator layer 42. The masks are then removed.

Various embodiments of the present invention may include conductivematerials for the various conductor patterns such as, for example, UVcurable conductive polymers such as Ablelux HGA-3A, photo-imageableconductive polymers, heat cured conductive polymers, Papinol'spolyaniline based inks, and/or silver, gold, aluminum, or Pd/Ptevaporated coatings. Various embodiments of the present invention mayinclude dielectric materials such as, for example, photo-imageablephotoresist such as Cyclotene (BCB) 4024-40, UV curable materials suchas Dupont BQ411, UV solder masks such as Lite Fast SR-1000, and/orelastomeric dielectric materials.

It can be understood that various techniques may be employed toconstruct a mesh on an electronic device without departing from theteachings of the present invention. For example, the mesh may beconstructed using various techniques that employ UV conductive polymers,and/or photo-imageable conductor polymers, evaporated coatings (thermalspray) of metals using, for example, e-beam technology or thermal ormagnetron (sputtering) in conjunction with masks. The conductive tracescan also be dispensed by depositing metal-filled or carbon-filledepoxies or other filled or otherwise conductive polymers by varioussyringe dispensing, screen printing and like methods. Also, it can beunderstood that the terminals 12 may be located randomly on any numberof surfaces of the device 10. Furthermore, it can be understood that theconductive traces may be formed in any suitable shape or pattern and bearranged in any suitable orientation. It can also be understood that thedielectric (non-conductive) layers can be dispensed by various printing,syringe dispensing, coating, or fluid dispensing methods. Numerous suchmethods should be obvious to one of average skill in the art.

The techniques and structures of the various embodiments of the presentinvention may be used to detect tampering of an electronic device. Inoperation and according to various embodiments of the present invention,a resistance value of a mesh that is located on the device may be knownafter the mesh is formed on the device. The resistance may be monitoredby, for example, a circuit located in the device and, if one or more ofthe lines of the mesh is broken or disrupted, a change in resistance canbe detected by the circuit. Such a circuit may be, for example, awheatstone bridge circuit. The mesh circuitry may also be monitored forchanges in the capacitance of the network. In this case, it may also bepossible to use the system of conducting mesh and dielectrics as aproximity detector.

It is to be understood that the figures and descriptions of embodimentsof the present invention have been simplified to illustrate elementsthat are relevant for a clear understanding of the present invention,while eliminating, for purposes of clarity, other elements. Those ofordinary skill in the art will recognize, however, that these and otherelements may be desirable for practice of various aspects of the presentembodiments. However, because such elements are well known in the art,and because they do not facilitate a better understanding of the presentinvention, a discussion of such elements is not provided herein.

It can be appreciated that, in some embodiments of the present methodsand systems disclosed herein, a single component can be replaced bymultiple components, and multiple components replaced by a singlecomponent, to perform a given function or functions. Except where suchsubstitution would not be operative to practice the present methods andsystems, such substitution is within the scope of the present invention.

Examples presented herein, including operational examples, are intendedto illustrate potential implementations of the present method and systemembodiments. It can be appreciated that such examples are intendedprimarily for purposes of illustration. No particular aspect or aspectsof the example method, product, and/or system embodiments describedherein are intended to limit the scope of the present invention.

It should be appreciated that figures presented herein are intended forillustrative purposes and are not intended as construction drawings.Omitted details and modifications or alternative embodiments are withinthe purview of persons of ordinary skill in the art. Furthermore,whereas particular embodiments of the invention have been describedherein for the purpose of illustrating the invention and not for thepurpose of limiting the same, it will be appreciated by those ofordinary skill in the art that numerous variations of the details,materials and arrangement of parts/elements/steps/functions may be madewithin the principle and scope of the invention without departing fromthe invention as described in the appended claims.

1. An electronic device, comprising: at least one terminal formed on theelectronic device, the electronic device comprising at least one of asemiconductor device, an integrated circuit chip, and a computer; and aplurality of conductive mesh layers formed on at least one surface ofthe electronic device, wherein the plurality of conductive mesh layersare in electrical contact with the terminal, and wherein the terminalfacilitates electrical conduction between the conductive mesh and anelectrical detection circuit wherein each of the plurality of conductivemesh layers comprises at least two layers of conductive patterns and anon-conductive layer formed between the at least two layers ofconductive patterns.
 2. The electronic device of claim 1, wherein theseamless conductive mesh is formed of a curable polymeric material. 3.The electronic device of claim 1, wherein the non-conductive layercomprises a dielectric material.
 4. The electronic device of claim 3,wherein the dielectric material has elastomeric properties.
 5. Theelectronic device of claim 1, wherein the electrical detection circuitis configured to detect a change in at least one of a resistance and aconductance of the conductive mesh.
 6. The electronic device of claim 1,wherein the electrical detection circuit is configured to detect achange in capacitance caused by a disruption of at least one of aconductive mesh layer and a non-conductive layer.
 7. The electronicdevice of claim 1, wherein the conductive mesh is arranged in one of acrisscross pattern, a crosshatch pattern, a serpentine pattern, awave-like pattern, a comb pattern, a multi-comb pattern, and a randomswirl pattern.
 8. An electronic device, comprising: a plurality ofconductive pattern layers formed on at least two surfaces of theelectronic device, the electronic device comprising at least one of asemiconductor device, an integrated circuit chip, and an electronicsubstrate, each of the plurality of conductive patterns comprising oneor more than one conductive traces, each of the one or more than oneconductive traces comprising a continuous loop of conductive materialand being formed on at least two surfaces of the electronic device,wherein a non-conductive layer is formed between adjacent layers of theplurality of conductive pattern layers.
 9. The electronic device ofclaim 8, further comprising a terminal formed on the electronic device,wherein the terminal facilitates electrical conduction between the oneor more than one traces and an electrical detection circuit.
 10. Theelectronic device of claim 9, wherein the electrical detection circuitis configured to detect a change in at least one of a resistance and aconductance of the pattern.
 11. The electronic device of claim 8,wherein the non-conductive layer comprises a dielectric material. 12.The electronic device of claim 11, wherein the dielectric material haselastomeric properties.
 13. The electronic device of claim 8, whereinthe electrical detection circuit is configured to detect a change incapacitance caused by a disruption of at least one of the plurality ofconductive pattern layers and a non-conductive layer.
 14. An electronicdevice, comprising: a first plurality of conductive loops formed on theelectronic device, each of the first plurality of conductive loopscontinuous and surrounding the electronic device in a first direction,the electronic device comprising at least one of a semiconductor device,an integrated circuit chip, and an electronic substrate; and a secondplurality of conductive loops formed on the electronic device, each ofthe second plurality of conductive loops continuous and surrounding theelectronic device in a second direction; and a non-conductive layerformed between the first plurality of conductive loops and the secondplurality of conductive loops.
 15. The electronic device of claim 14,wherein the first direction is different than the second direction. 16.The electronic device of claim 14, further comprising a terminal formedon the electronic device, wherein the terminal facilitates electricalconduction between the first plurality of conductive loops, the secondplurality of conductive loops, and an electrical detection circuit,wherein the electrical detection circuit is configured to detect achange in at least one of a resistance and a conductance of the pattern.17. The electronic device of claim 14, wherein the electrical detectioncircuit is configured to detect a change in capacitance caused by thedisturbance of at least one of the first plurality of conductive loops,the second plurality of conductive loops, and the non-conductive layer.